Bit for rotary cutter-heads.



No. 841.587. PATENTED JAN. 15, 1907. E. S. SHIMER.

BIT FOR ROTARY CUTTER HEADS.

APPLICATION FILED OCT. 31 1906.

SHEETS-SHEET l.

PATENTED JAN. 15, 1907.

E. S. SHIMER.

BIT EOE ROTARY CUTTER HEADS.

APPLICATION FILED 0CT.31- 1906.

2 SHEETS-SHEET 2.

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rinrrnn srarns PATENT orrron ELMER S. SHIMER, OF MILTON, PENNSYLVANIA, ASSIGNOR TO SAMUEL J. SHIMER AND SONS, INCORPORATED, OF MILTON, PENNSYLVANIA.

BiT FOR ROTARY CUTTER-HEADS.

Specification of Letters Patent.

Patented Jan. 15, 19057.

Application filed October 31, 1906. Serial No. 341,462.

To all whom it may concern.-

Be it known that I, ELMER S. SHIMER, a citizen of the United States, residing at Milton, in the county of N orthumberland and State of Pennsylvania, have invented certain new and useful Improvements in Knives or Bits for Rotary Cutter-Heads, of which the following is a specification.

This invention relates to knives or bits for use in rotary cutter-heads in dressing, molding, and matching lumber and the invention has particular reference to molding and matching bits having interrupted or irregular cutting edges or to knives or bits in general having sharp corners or square offsets. In resharpening bits of this character it is essential that the initial distance between the original angles, corners, or ofl'sets of the cutting edge be maintained, inasmuch as unless this is done the contour of the cutting edge would obviously be changed. Heretofore those whose task it has been to resharpen the bits have done so largely by eye-measure, and the operation of resharpening the bits has been one requiring extra-skilled. and highlypaid labor.

The principal object of the present invention is to provide permanent and distinctly visible marks in the face of the bit which shall serve to guide the operator in grinding back the cutting edge, so that by the exercise of reasonable care the original contour of the cutting edge may be maintained. The marks and lines so placed upon the face of the knives will appear only at a square oil set or at a union of two curved lines effecting a sharp point in the knife-pattern. These lines will therefore leave no visible trace of their existence upon the finished lumber by reason of their p articular location or position.

The invention will be fully and clearly described in the following part of the specification, reference being had to the accompanying drawings, in which- Figures 1, 2, 3, and 4 are plan views of molding-bits constructed in accordance with the principles of the invention and having cutting edges of different contours. Figs. 5, 6, 7, and 8 are transverse sectional views of said bits. Fig. 9 is a longitudinal sectional view of one of the bits, taken on the plane indicated by the line 9 9 in Fig. 1. Fig. 10 is a perspective view of a matching-bit or tonguehead bit constructed in accordance with the invention. Fig. 11 is a plan view of the same. Fig. 12 is a cross-section taken on the plane indicated by the line 12 12 in Fig. 1 1.

Corresponding parts in the several figures are denoted by like characters of referonce.

The molding-bits A A are provided with cutting edges 1 1 of different contours, and the cutting ends of said bits are beveled back from the cutting edges, as will be seen at 2. Some of the bits have been shown equipped with slots 3 for the passage of fastening means, such as bolts, whereby they may be mounted for operation in cutter-heads of suitable construction; but the means for mounting the bits have not been shown and do not constitute a part of the present invention.

The cutting edges of the bits may be of any desired and appropriate contour or outline, the same having been shown in each instance as including one or more angles or ofisets 4, the points 4 being joined by straight or curved lines, as the case may be. The edges 5 and 6 of each bit are parallel to each other, and in the face of each bit there are formed slender but clearly visible and appreciable grooves or scores 7, intersecting the angles or corners 4 and leading back from the latter, said rooves or scores being formed parallel to each other and also parallel to the edges 5 and 6 of the bits. The grooves or scores 7 may be formed in any suitable and convenient manner by indenting the metal or by removing a portion of the same, and the precise manner of forming the said grooves or scores is immaterial to the present invention.

It will be readily seen that the grooves or scores 7 will form permanent markers 01 liners to guide the operator in sharpening the bit fromtime to time as it wears back. With these permanently-fixed points before his eyes the operator may readily trace the connecting lines, and the process of sharpening the bit may be carried out easily and quickly and with a degree of accuracy which has heretofore been practically unattainable.

In Figs. 10, 11, and 12 of the drawings the invention has been shown as applied to a matching-bit of that class which are known as tongue-head bits and which are used for the purpose of initially forming or roughing out tongues upon the edges of boards and other lumber. In this bit the cutting end S is beveled backward from the cutting edge, Which latter is divided into upper and lower portions 9 and 10 by the intervening notch or recess 11, the bottom of Which is generally incidentally beveled; but it is not designed nor allowed to perform any cutting. The said recess must be Wide enough to leave a tongue of the desired Width of the lumber,

and such recess must further be located WitheXactness, so that the tongue may be formed on the edge of the boards in precisely the place determined upon in calculations made before beginning Work. Furthermore, the side Walls of the notch or recess must be precisely parallel in order that the bit may operate smoothly and efficiently.

By reason of the hardness and toughness of the steel used in the manufacture of these bits they can be sharpened When they become too dull for use only by grinding on the grindstone or emery-Wheel. When the cutting edges of the portions 9 and 10 are ground for the purpose of sharpening them, it is necessary to grind the bottom of the notch or recess 11 back correspondingly, so that it shall not touch the outer edge of the tongue formed on the edge of the boards. In the performance of this latter Work, however, there is ordinarily much danger of cutting the side Walls of the notch out of parallelism, and s0 disturbing the position of the notch, and consequently the position and form of the tongue made. hen this happens, the bit is destroyed and must be cast aside. This difficulty and the loss occasioned thereby is obviated by forming parallel scores or indentations 12 in the face of the bit, said scores being of appreciable depth and leading back from the inner corners of the notch or recess 11, so as to form an absolutely correct gage or guide to the grinder, making it impossible for him Without the grossest careless ness .to go Wrong in grinding back the notch, as before stated.

The invention, as Will be seen from the foregoing, is applicable to various kinds and forms of knives or bits, it being understood that the indentations or scores serving to form guides in resharpening may be formed or located Wherever it shall be found desirable. While the invention is simple in its nature, it is of high importance, especially in these times When exactness and perfection is required in tools that are used in making goods manufactured for the market, When the slightest discoverable defect in said manufactures Will occasion'their condemnation as seconds or from sale and use altogether and When profits are secured only by the small savings that can be made over the ordinary expense in conducting business.

Having thus described the invention,what is claimed is 1. A bit for cutter-heads having a cutting edge of irregular contour and provided in the face thereof with scoresor indentations lead.- ing back from the angles or offsets of the cutting edge.

2. A bit for rotary cutter-heads having an irregular or interrupted cuttin edge and pro vided in the face thereof Wit scores or indentations leading back from the angles or offsets of the cutting edge, said scores or indentations being parallel to each other and to the edges of the bit.

3. A bit for rotary cutter-heads having an irregular or interrupted cutting edge and provided in the face thereof With permanent lines or markers leading back from the an gles or offsets of the cutting edge and forming guides for grinding or resharpening the cutting edge.

4. An edged tool having an irregular or interrupted cutting edge, the face of said tool being provided With scores or indentations parallel to each other and to the edges of the tool, and leading back from the angles or off sets of the cutting edge.

5. A bit consisting of a straight, fiat piece of hard steel having a notch formed in its cutting end and having parallel scores formed on the face thereof, said scores leading back from the corners of the notch in alinement With the side Walls of the latter.

In testimony Whereof I have signed my name to this specification in the presence of tWo subscribing Witnesses.

ELMER S. SHIMER.

Witnesses WV. H. BECK, FRANK LONGMORE. 

